# The first complete mitochondrial genome and phylogenetic analysis of deep-sea asteroid, Leptychaster arcticus (Valvatacea: Paxillosida: Astropectinidae)

## TL;DR

This paper presents the first complete mitochondrial genome of the deep-sea asteroid Leptychaster arcticus and explores its phylogenetic relationships.

## Contribution

The study provides the first complete mitogenome of L. arcticus and highlights its phylogenetic implications for deep-sea echinoderms.

## Key findings

- The mitogenome is 16,253 bp long with typical gene content and no rearrangements.
- The ND4L and ND3 genes use the 'ATT' start codon, a common feature in echinoderm mitogenomes.
- Phylogenetic analysis at lower taxonomic levels remains unresolved due to limited asteroid data.

## Abstract

The complete mitochondrial genome of Leptychaster arcticus, deep-sea inhabited asteroid, was examined in this study. The complete mitogenome of L. arcticus is 16,253 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes. No gene rearrangements or deletions were observed in compared to other Paxillosida. The ND4L and ND3 genes have ‘ATT’ as its start codon, which is a feature that has been found in previous echinoderm mitochondrial studies. In the ML tree analysis based on the superorder Valvatacea, it was difficult to establish the molecular phylogenetic relationship at lower taxonomic levels, such as order and family, due to the lack of asteroid molecular data available. Therefore, we expect to contribute to the expansion of the data and determine the phylogenetic positioning in future studies.